// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/test/url_request/url_request_mock_http_job.h"

#include "base/files/file_util.h"
#include "base/macros.h"
#include "base/message_loop/message_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task_runner_util.h"
#include "base/threading/sequenced_worker_pool.h"
#include "base/threading/thread_restrictions.h"
#include "net/base/filename_util.h"
#include "net/base/net_errors.h"
#include "net/base/url_util.h"
#include "net/http/http_response_headers.h"
#include "net/url_request/url_request_filter.h"
#include "net/url_request/url_request_interceptor.h"

namespace net {

namespace {

    const char kMockHostname[] = "mock.http";
    const base::FilePath::CharType kMockHeaderFileSuffix[] = FILE_PATH_LITERAL(".mock-http-headers");

    class MockJobInterceptor : public URLRequestInterceptor {
    public:
        // When |map_all_requests_to_base_path| is true, all request should return the
        // contents of the file at |base_path|. When |map_all_requests_to_base_path|
        // is false, |base_path| is the file path leading to the root of the directory
        // to use as the root of the HTTP server.
        MockJobInterceptor(
            const base::FilePath& base_path,
            bool map_all_requests_to_base_path,
            const scoped_refptr<base::SequencedWorkerPool>& worker_pool)
            : base_path_(base_path)
            , map_all_requests_to_base_path_(map_all_requests_to_base_path)
            , worker_pool_(worker_pool)
        {
        }
        ~MockJobInterceptor() override { }

        // URLRequestJobFactory::ProtocolHandler implementation
        URLRequestJob* MaybeInterceptRequest(
            URLRequest* request,
            NetworkDelegate* network_delegate) const override
        {
            return new URLRequestMockHTTPJob(
                request,
                network_delegate,
                map_all_requests_to_base_path_ ? base_path_ : GetOnDiskPath(request),
                worker_pool_->GetTaskRunnerWithShutdownBehavior(
                    base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
        }

    private:
        base::FilePath GetOnDiskPath(URLRequest* request) const
        {
            // Conceptually we just want to "return base_path_ + request->url().path()".
            // But path in the request URL is in URL space (i.e. %-encoded spaces).
            // So first we convert base FilePath to a URL, then append the URL
            // path to that, and convert the final URL back to a FilePath.
            GURL file_url(FilePathToFileURL(base_path_));
            std::string url = file_url.spec() + request->url().path();
            base::FilePath file_path;
            FileURLToFilePath(GURL(url), &file_path);
            return file_path;
        }

        const base::FilePath base_path_;
        const bool map_all_requests_to_base_path_;
        const scoped_refptr<base::SequencedWorkerPool> worker_pool_;

        DISALLOW_COPY_AND_ASSIGN(MockJobInterceptor);
    };

    std::string DoFileIO(const base::FilePath& file_path)
    {
        base::FilePath header_file = base::FilePath(file_path.value() + kMockHeaderFileSuffix);

        if (!base::PathExists(header_file)) {
            // If there is no mock-http-headers file, fake a 200 OK.
            return "HTTP/1.0 200 OK\n";
        }

        std::string raw_headers;
        base::ReadFileToString(header_file, &raw_headers);
        return raw_headers;
    }

    // For a given file |path| and |scheme|, return the URL served by the
    // URlRequestMockHTTPJob.
    GURL GetMockUrlForScheme(const std::string& path, const std::string& scheme)
    {
        return GURL(scheme + "://" + kMockHostname + "/" + path);
    }

} // namespace

// static
void URLRequestMockHTTPJob::AddUrlHandlers(
    const base::FilePath& base_path,
    const scoped_refptr<base::SequencedWorkerPool>& worker_pool)
{
    // Add kMockHostname to URLRequestFilter, for both HTTP and HTTPS.
    URLRequestFilter* filter = URLRequestFilter::GetInstance();
    filter->AddHostnameInterceptor(
        "http", kMockHostname, CreateInterceptor(base_path, worker_pool));
    filter->AddHostnameInterceptor("https", kMockHostname,
        CreateInterceptor(base_path, worker_pool));
}

// static
GURL URLRequestMockHTTPJob::GetMockUrl(const std::string& path)
{
    return GetMockUrlForScheme(path, "http");
}

// static
GURL URLRequestMockHTTPJob::GetMockHttpsUrl(const std::string& path)
{
    return GetMockUrlForScheme(path, "https");
}

// static
std::unique_ptr<URLRequestInterceptor> URLRequestMockHTTPJob::CreateInterceptor(
    const base::FilePath& base_path,
    const scoped_refptr<base::SequencedWorkerPool>& worker_pool)
{
    return std::unique_ptr<URLRequestInterceptor>(
        new MockJobInterceptor(base_path, false, worker_pool));
}

// static
std::unique_ptr<URLRequestInterceptor>
URLRequestMockHTTPJob::CreateInterceptorForSingleFile(
    const base::FilePath& file,
    const scoped_refptr<base::SequencedWorkerPool>& worker_pool)
{
    return std::unique_ptr<URLRequestInterceptor>(
        new MockJobInterceptor(file, true, worker_pool));
}

URLRequestMockHTTPJob::URLRequestMockHTTPJob(
    URLRequest* request,
    NetworkDelegate* network_delegate,
    const base::FilePath& file_path,
    const scoped_refptr<base::TaskRunner>& task_runner)
    : URLRequestFileJob(request, network_delegate, file_path, task_runner)
    , task_runner_(task_runner)
    , weak_ptr_factory_(this)
{
}

URLRequestMockHTTPJob::~URLRequestMockHTTPJob()
{
}

// Public virtual version.
void URLRequestMockHTTPJob::GetResponseInfo(HttpResponseInfo* info)
{
    // Forward to private const version.
    GetResponseInfoConst(info);
}

bool URLRequestMockHTTPJob::IsRedirectResponse(GURL* location,
    int* http_status_code)
{
    // Override the URLRequestFileJob implementation to invoke the default
    // one based on HttpResponseInfo.
    return URLRequestJob::IsRedirectResponse(location, http_status_code);
}

// Public virtual version.
void URLRequestMockHTTPJob::Start()
{
    base::PostTaskAndReplyWithResult(
        task_runner_.get(),
        FROM_HERE,
        base::Bind(&DoFileIO, file_path_),
        base::Bind(&URLRequestMockHTTPJob::SetHeadersAndStart,
            weak_ptr_factory_.GetWeakPtr()));
}

void URLRequestMockHTTPJob::SetHeadersAndStart(const std::string& raw_headers)
{
    raw_headers_ = raw_headers;
    // Handle CRLF line-endings.
    base::ReplaceSubstringsAfterOffset(&raw_headers_, 0, "\r\n", "\n");
    // ParseRawHeaders expects \0 to end each header line.
    base::ReplaceSubstringsAfterOffset(
        &raw_headers_, 0, "\n", base::StringPiece("\0", 1));
    URLRequestFileJob::Start();
}

// Private const version.
void URLRequestMockHTTPJob::GetResponseInfoConst(HttpResponseInfo* info) const
{
    info->headers = new HttpResponseHeaders(raw_headers_);
}

bool URLRequestMockHTTPJob::GetMimeType(std::string* mime_type) const
{
    HttpResponseInfo info;
    GetResponseInfoConst(&info);
    return info.headers.get() && info.headers->GetMimeType(mime_type);
}

int URLRequestMockHTTPJob::GetResponseCode() const
{
    HttpResponseInfo info;
    GetResponseInfoConst(&info);
    // If we have headers, get the response code from them.
    if (info.headers.get())
        return info.headers->response_code();
    return URLRequestJob::GetResponseCode();
}

bool URLRequestMockHTTPJob::GetCharset(std::string* charset)
{
    HttpResponseInfo info;
    GetResponseInfo(&info);
    return info.headers.get() && info.headers->GetCharset(charset);
}

} // namespace net
